Apparatus for grinding drill bits



Nov. 29, 1955 A. H. BRANDT ETAL 2,724,931

APPARATUS FOR GRINDING DRILL BITS Filed A m 22, 1954 2 Sheets-Sheet 1 FIEJL 9208 5. AXEL H. BRA/V07 and HE M? Y R. F ORSBE R6 deceased,

Nov. 29, 1955 A. H. BRANDT ETAL APPARATUS FOR GRINDING DRILL ans 2 Sheets-Sheet 2 Fild April 22, 1954 lnueidmzs. AXEL H. BRANDT and HENRY R. F ORSBE R6 deceased, By. KA THEE/IVE L. FQRSBERG, adm/ lsfrafrlx Awe/ 5 United States Patent APPARATUS FOR GRINDING DRILL BITS Axel H. Brandt, Virginia, and Henry R. Forsberg, deceased, late of Leoneth, Minn, by Katherine L. Forsberg, administratrix, Leoneth, Minn.

Application April 22, 1954, Serial No. 424,984

2 Claims. (Cl. 51122) This invention relates to an improved apparatus for grinding drill bits.

An object of the invention is to provide an improved grinding apparatus which affords maximum flexibility in positioning a drill bit for contact with a grinding Wheel.

A further object is to provide an improved grinding apparatus in which the grinding wheel is mounted on a tiltable platform and the Work is mounted on a slide adjustable horizontally in two directions.

In accomplishing these and other objects of the invention, We have provided improved details of structure, a preferred form of which is shown in the accompanying drawings, in which:

Figure l is a top plan view of our grinding apparatus;

Figure 2 is a vertical section on line II-II of Figure l; and

Figure 3 is an end elevational view.

Our grinding apparatus includes a stand which carries support means, hereinafter described, for a grinding wheel 12 and a bit positioner 13. Both the grinding wheel and the bit positioner per se can be of any standard or desired construction and hence are not shown nor described in detail. The bit positioner illustrated is a type manufactured by Ingersoll-Rand Company and it includes an indexing head 14 which is adapted to position a drill bit B in contact with the periphery of the grinding wheel at the various angles required for grinding its several cutting edges.

In accordance with our invention, the support means for the grinding wheel 12 comprises a platform 15 hinged to the stand 10 on a horizontal axis along one side edge, as indicated at 16 (Figures 1 and 3). This platform carries vertical walls 17 which support a pair of spaced apart bearings 18. The grinding wheel 12 is fixed to one end of a shaft 19, which is journaled in the bearings 18 and extends parallel to the axis of hinging 16. The platform 15 also carries a motor 20 which is connected to the shaft 19 through a belt and pulley mechanism 21. The underside of the platform 15 carries a pair of depending gear racks 22. A hand wheel 23 is rotatably mounted on the stand 10 and connected to a speed reducer 24, preferably of the worm gear type. The latter carries a pair of pinions 25 which engage the respective gear racks 22. Thus rotation of the hand wheel 23 tilts the platform 15 about the axis 16 and raises or lowers the grinding wheel 12.

Also in accordance with our invention, the support means for the bit positioner 13 comprises a table 26 mounted on the stand 10 for horizontal adjustment in a direction perpendicular to the axis of hinging 16, and a slide 27 mounted on said table for horizontal adjustment 2,724,931 Patented Nov. 29, 1955 in a direction parallel to said axis. The mounting for the table includes a pair of rails 28 fixed to the stand 10 and a plurality of rollers 29 carried by the table and riding on said rails. The table carries a gear rack 30 which extends along its front edge. The stand 10 carries a hand wheel 31 and a pinion 32 which cooperates with the gear rack 30 for moving the table. The mounting for the slide 27 includes a pair of guides 33 fixed to the table 26 along its opposite edges. A screw threaded spindle 34 is journaled to the front edge of the slide and threadedly engaged with a nut 35 which is fixed to the table 26. Said spindle carries a hand wheel 36. The upper face of the slide carries a fixture 37 on which the bit positioner 13 is mounted. By operation of the two hand wheels 31 and 36, the horizontal position of the bit positioner 13 can be varied as desired with respect to the grinding wheel 12.

Our grinding apparatus enables the grinding wheel to be adjusted vertically with respect to a drill bit, and the drill bit to be adjusted horizontally in two directions with respect to the grinding Wheel. Thus it affords the maximum flexibility in positioning the bit for contact with the wheel and enables the cutting edges to be ground accurately.

While we have shown and described only a single embodiment of the invention, it is apparent that modifications may arise. Therefore, we do not wish to be limited to the disclosure set forth but only by the scope of the appended claims.

What is claimed is:

l. A tool grinder for grinding drill bits comprising a stand, a platform hinged along one of its edges to the top of said stand for movement on a horizontal axis, a drive motor mounted on said platform, upstanding support means carried by said platform, a shaft journaled in said support means above said motor and rotatable on an axis parallel to said first named axis, a transmission connection for driving said shaft from said motor, a grinding Wheel carried by one end of said shaft, means spaced from said first named axis for tiltably adjusting said platform about this axis and thus varying the vertical position of said wheel, a table mounted on the top of said stand below said wheel for horizontal adjustment alongside said platform, a slide mounted on said table for horizontal adjustment, one of the horizontal adjustments being in a direction parallel to said first named axis and the other being at a right angle thereto, and a drill bit positioner carried by said slide, said positioner including an indexing head adapted to position a bit in contact with said wheel at the various angles required for grinding its several cutting edges.

2. A grinder as defined in claim 1 in which the means for tiltably adjusting the platform includes a pair of gear racks depending from the platform, a shaft journaled to said stand, pinions carried by said shaft and meshing with said racks, and a hand drive and speed reducer for turning said last named shaft.

References Cited in the file of this patent UNITED STATES PATENTS 614,247 Goodhew et al Nov. 15, 1898 1,963,394 Yassenoff June 19, 1934 2,199,773 Armand May 7, 1940 2,386,283 Wiken et a1 Oct. 9, 1945 2,458,840 Eklund Jan. 11, 1949 

